Blueberries are members of the genus Vaccinium, which includes huckleberries and cranberries. Deciding on a variety of blueberry to grow often depends on where you live, as some are better for colder climates than others. Most blueberry species fall under one of five categories: northern highbush, southern highbush, rabbiteye, lowbush or half-high.
Northern highbush, or standard highbush, is one of the most popular blueberry varieties. Its name comes from its erect bushes that grow 6 to 12 feet high. It has the longest chilling time: between 800 to 1,100 hours. Chilling time is the total number of hours below 45 degrees F during the dormant season. For this reason, it is primarily grown in northern states, although it can be grown anywhere in USDA zones 4 through 7. Highbush blueberries are self-pollinating but produce better if another variety is planted nearby. The berries range in size form 1/2 to 1 inch in diameter and are blue-black in color. Fruit matures in 45 to 75 days after flowering, depending on if the variety is early, mid- or late ripening.
The southern highbush is a cross between the northern highbush (V. corymbosum) and southern-loving, native species such as V. ashei, V. corymbosum, or V. darrowi. It was introduced in the 1970s. It is very similar to the northern highbush in appearance, berry size and ripening period. The major difference of the northern and southern highbush is the chilling time. Southern highbush has a shorter chilling period of 200 to 700 hours, which means it can be grown in USDA zones 6b through 10.
Rabbiteye blueberries (Vaccinium ashei) are tall, deciduous shrubs native to the Southeastern United States. They can reach up to 20 feet tall in the wild and have a seven-year productive life. Its fruit is good quality, blue-black in color and matures about 90 days after flowering. No major pests have been identified for rabbiteyes. They require between 350 to 800 chilling hours, depending on the variety. Rabbiteye is grown primarily in Florida, Mississippi, North Carolina, Louisiana and southern Georgia.
Lowbush blueberries consist of several species, including V. angustifolium, V. myrtilloides, V. Brittonii and V. Lamarckii. They often are referred to as wild blueberries. These bushes are smaller than highbush blueberries, with heights varying between 1-1/2 to 8 feet. It is rhizomatous, meaning it has an underground stem below the surface which it uses for propagation. Lowbush blueberries are hardy in USDA zones 3 through 6. Berries are produced 70 to 90 days after blooms appear. They require 1,000 hours of chilling.
Half-high refers to the growing habit of some blueberries, created to satisfy the demand for smaller blueberry bushes. Most half-high blueberry plants are interspecifc hybrids of Vaccinium corymbosum x Vaccinium angustifolium. As such, they mix highbush's large fruit with lowbush's tolerance for the cold. The taste is somewhat between the two. They are hardy in USDA zones 3 through 7.